JP5257989B2 - Natural mountain stability evaluation method - Google Patents
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- 238000011156 evaluation Methods 0.000 title claims description 35
- 238000004458 analytical method Methods 0.000 claims description 77
- 238000005259 measurement Methods 0.000 claims description 51
- 238000010276 construction Methods 0.000 claims description 44
- 238000009412 basement excavation Methods 0.000 claims description 26
- 238000000034 method Methods 0.000 claims description 9
- 238000009434 installation Methods 0.000 claims description 6
- 238000000691 measurement method Methods 0.000 claims description 3
- 230000002787 reinforcement Effects 0.000 description 16
- 238000006073 displacement reaction Methods 0.000 description 7
- 238000011835 investigation Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000012423 maintenance Methods 0.000 description 3
- 230000006835 compression Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 239000013307 optical fiber Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000012669 compression test Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003673 groundwater Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000012552 review Methods 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
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Description
本発明は、切土または掘削施工時及び施工後の地山の安定性を評価するための地山安定性評価方法に関するものである。 The present invention relates to a natural ground stability evaluation method for evaluating the stability of natural ground during cutting or excavation construction and after construction.
道路建設や造成工事などの土工事においては、切土または掘削施工時及び施工後の地山の安定は重要な課題であり、近年、施工後の耐用年数の長期化及び維持コストの削減につながる高精度な地山安定性評価方法の開発が要求されている。 In earthwork such as road construction and creation work, the stability of natural ground during cutting or excavation construction and after construction is an important issue, and in recent years it will lead to longer service life after construction and reduction of maintenance costs. There is a need for the development of a highly accurate method for assessing natural ground stability.
切土または堀削施工により、地山は除荷(応力開放)によるリバウンド(地山の緩み)やすべりが発生して、潜在的に地山の内部に弱層が存在する場合には地山の安定性が低下することになる。それに併せて、雨水、地下水の浸透が、地山緩みによるクラックによって加速されると、弱層では吸水膨張によりさらに強度が低下する。 If the ground is rebounded (slack of the ground) or slips due to unloading (stress relief) due to cutting or excavation, the ground is potentially weak within the ground. This will reduce the stability. At the same time, when the penetration of rainwater and groundwater is accelerated by cracks caused by loosening of the natural ground, the strength is further reduced in the weak layer due to water absorption expansion.
そこで、従来の地山安定性評価方法は、基本的には、地山を切土または掘削施工する施工ステップと、地山の内部の変形を計測する計測ステップと、該変形データに基いて解析パラメータを逆解析する逆解析ステップと、該解析パラメータにより地山の安定性をFEM解析する解析ステップと、該解析結果に基いて地山の安定性を評価する安定性評価ステップとを備えている(非特許文献1参照)。 Therefore, the conventional method for evaluating the stability of natural ground is basically based on a construction step for cutting or excavating the natural ground, a measurement step for measuring deformation inside the natural ground, and an analysis based on the deformation data. A reverse analysis step for performing reverse analysis of the parameters, an analysis step for performing FEM analysis of the stability of the natural ground using the analysis parameters, and a stability evaluation step for evaluating the stability of the natural ground based on the analysis result. (Refer nonpatent literature 1).
従来の地山安定性評価方法における計測ステップでは、主に、ボーリング孔を利用した傾斜計による変位計測または地中ひずみ計によるひずみ計測が行われている。しかしながら、前者の変位計測による計測データに基いて、FEM解析に必要な解析パラメータを逆解析しようとする場合、該計測データでは、地山の不均質な各地質の応力−ひずみ特性(各地質の材料特性)を逆解析することが難しい。すなわち、この計測データ(変位)は各地質の変位角の積分値であるため、この計測データから不均質の各地質の応力−ひずみ特性を逆解析することは困難であった。
一方、後者の地中ひずみ計においては、物理的な制約からひずみ計測点の間隔が大きく(1m程度)なるために、切土または掘削施工によって発生するひずみレベルであると、ひずみの発生は検知できるもののひずみ量及び方向などを高精度に計測することが不可能である。
In the measurement step in the conventional natural ground stability evaluation method, displacement measurement by an inclinometer using a borehole or strain measurement by an underground strain gauge is mainly performed. However, when the analysis parameters necessary for the FEM analysis are to be back-analyzed based on the measurement data obtained by the former displacement measurement, in the measurement data, the stress-strain characteristics of the heterogeneous local geology ( It is difficult to reverse analyze (material properties). That is, since this measurement data (displacement) is an integral value of the displacement angle of each geological quality, it is difficult to reverse-analyze the stress-strain characteristics of the heterogeneous geological quality from this measurement data.
On the other hand, in the latter underground strain gauge, the distance between the strain measurement points becomes large (about 1 m) due to physical constraints, so that the occurrence of strain is detected when the strain level is generated by cutting or excavation. It is impossible to measure the strain amount and direction of what can be done with high accuracy.
しかも、前者の傾斜計による変位計測及び後者の地中ひずみ計によるひずみ計測の両者とも、深度方向(ボーリング孔の軸方向)に対して直交する方向の変位またはひずみしか計測できないため、除荷に伴う地山のリバウンド挙動(膨張)を計測するには不向きである。さらに、これらの計測方法では、応力開放に伴うリバウンド挙動とすべり挙動との判別が難しく、かつ地山挙動は、切土または掘削施工がある程度進行してから反応し始めるため、地山のリバウンド挙動による緩みを連続的に把握することが困難であり、深度方向のひずみを併せて計測する必要があった。 Moreover, both the displacement measurement with the former inclinometer and the strain measurement with the latter underground strain gauge can only measure displacement or strain in the direction perpendicular to the depth direction (the axial direction of the borehole). It is not suitable for measuring the rebound behavior (expansion) of the natural ground. Furthermore, with these measurement methods, it is difficult to distinguish between rebound behavior and slip behavior associated with stress release, and the natural ground behavior begins to react after some progress in cut or excavation. It was difficult to keep track of the slack due to the depth, and it was necessary to measure the strain in the depth direction.
また、従来の地山安定性評価方法に採用されたFEM解析ステップでは、線形弾性などの非常に単純化した解析手法が採用されており、上述した計測ステップにて計測した地山の変位量から地山の単純な材料特性等の解析パラメータを逆解析ステップにて逆解析して、該解析パラメータに基いてFEM解析が行われていた。そのため、地山内の各地質の応力−ひずみ特性(詳細な材料特性)等が全然反映されておらず、その解析結果の信頼性(予測精度)が低かった。 Moreover, in the FEM analysis step adopted in the conventional method for evaluating natural ground stability, a very simplified analysis method such as linear elasticity is adopted, and the displacement amount of the natural ground measured in the above measurement step is used. An analysis parameter such as a simple material characteristic of a natural ground is inversely analyzed in an inverse analysis step, and FEM analysis is performed based on the analysis parameter. For this reason, the stress-strain characteristics (detailed material characteristics) of the various qualities in the ground are not reflected at all, and the reliability (prediction accuracy) of the analysis results is low.
上述したように、従来の地山安定性評価方法では、特に、計測ステップにて、深度に対するひずみを高精度に計測することができず、また、解析ステップにて解析される解析結果においても信頼性が低く、切土または掘削施工時及び施工後の地山の安定性を高い精度で評価することが困難であった。 As described above, in the conventional ground stability evaluation method, it is not possible to measure the strain with respect to the depth with high accuracy, particularly in the measurement step, and the analysis result analyzed in the analysis step is reliable. Therefore, it was difficult to evaluate the stability of natural ground during cutting or excavation construction and after construction with high accuracy.
本発明は、かかる点に鑑みてなされたものであり、切土または掘削施工時及び施工後の地山安定性を高い精度で評価可能な地山安定性評価方法を提供することを目的とする。 This invention is made | formed in view of this point, and it aims at providing the natural ground stability evaluation method which can evaluate the natural ground stability at the time of cutting or excavation construction and after construction with high precision. .
本発明は、上記課題を解決するための手段として、請求項1に記載した発明は、切土または掘削施工時及び施工後の深度方向のひずみと、該深度方向に対して直交する方向のひずみの計測が可能な既存計測手法を採用し、地山の安定性を評価する地山安定性評価方法であって、地山の内部に、深度に対するひずみを計測可能なひずみ計測センサーを設置するセンサー設置ステップと、該センサー設置ステップ後、地山を切土または掘削施工する施工ステップと、該施工ステップ後、前記ひずみ計測センサーにより地山の深度に対するひずみを計測するひずみ計測ステップと、該ひずみ計測ステップによる計測結果に基いて、弾塑性FEM解析に必要な解析パラメータを逆解析する逆解析ステップと、該逆解析ステップにて逆解析した解析パラメータに基いて、切土または掘削施工による地山の安定性を弾塑性FEMにより解析する解析ステップと、を備えたことを特徴とするものである。
請求項1の発明では、特に、計測ステップにて、ひずみ計測センサーを採用して地山内部の深度に対するひずみを計測しているので、従来不可能であった、不均質な各地質の応力−ひずみ特性の解析パラメータを逆解析することが可能であり、しかも、解析ステップでは、切土または掘削施工によるリバウンド挙動や弱層の剛性低下などのすべり挙動等を高い精度で予測可能な弾塑性FEMが採用され、該弾塑性FEMにおいて、不均質な各地質の応力−ひずみ特性等の解析パラメータにより地山挙動を解析するので、切土または掘削施工時及び施工後の地山の安定性を高い精度で評価することができる。
本発明の地山安定性評価方法に用いるひずみ計測センサーとしては、例えば、光ファイバセンサー(特開2006−38794号公報)がある。
As a means for solving the above-mentioned problems, the present invention described in claim 1 is a strain in the depth direction at the time of cutting or excavation construction and after construction, and strain in a direction perpendicular to the depth direction. This is a natural-stable stability evaluation method that uses existing measurement methods that can measure the ground and evaluates the stability of natural ground. A sensor that installs a strain measurement sensor that can measure strain against depth inside the natural ground. An installation step, a construction step for cutting or excavating a natural ground after the sensor installation step, a strain measuring step for measuring strain with respect to the depth of the natural ground by the strain measurement sensor after the construction step, and the strain measurement Based on the measurement result of the step, the inverse analysis step for inverse analysis of the analysis parameters necessary for the elasto-plastic FEM analysis, and the analysis parameter reversely analyzed at the inverse analysis step Based on over data, it is characterized in that it comprises an analysis step of the stability of the natural ground by the Cut or excavation construction analyzed by elastoplastic FEM, a.
In the first aspect of the invention, in particular, since a strain measurement sensor is used in the measurement step to measure the strain with respect to the depth inside the natural ground, the stress of non-homogeneous local quality, which has been impossible in the past, is not possible. It is possible to reverse-analyze the analysis parameters of the strain characteristics, and in the analysis step, elastic-plastic FEM that can predict the rebound behavior due to cutting or excavation construction and the slip behavior such as weak rigidity of the weak layer with high accuracy In the elasto-plastic FEM, the natural ground behavior is analyzed by analysis parameters such as stress-strain characteristics of heterogeneous local quality, so the stability of natural ground during cutting or excavation construction and after construction is high. Can be evaluated with accuracy.
As a strain measurement sensor used for the natural ground stability evaluation method of the present invention, for example, there is an optical fiber sensor (Japanese Patent Laid-Open No. 2006-38794).
請求項2に記載した発明は、請求項1に記載した発明において、前記解析ステップによる解析結果の妥当性を評価する妥当性評価ステップと、該妥当性評価ステップにて、解析結果に妥当性があると判断された場合には該解析結果に基いて地山の安定性を評価する安定性評価ステップと、を備えたことを特徴とするものである。
請求項2の発明では、信頼性の高い地山安定性の評価が可能であるので、施工時の補強工事の有無を判断できると共に、補強工事の内容についても最適なものを選択することができ、しかも、施工後の耐用年数の長期化及び維持コストの削減が可能になる。
The invention described in claim 2 is the invention described in claim 1, wherein the validity of the analysis result is evaluated in the validity evaluation step for evaluating the validity of the analysis result in the analysis step, and the validity evaluation step. A stability evaluation step for evaluating the stability of the natural ground on the basis of the analysis result when it is determined that it is present.
In the invention of claim 2, since it is possible to evaluate the reliability of the ground with high reliability, it is possible to determine the presence or absence of the reinforcement work at the time of construction and to select the optimum contents of the reinforcement work. In addition, the service life after construction can be extended and maintenance costs can be reduced.
請求項3に記載した発明は、請求項1または2に記載した発明において、前記逆解析ステップは、深度方向のひずみと、該深度方向に対して直交する方向のひずみ計測結果に基いて実施されることを特徴とするものである。 The invention described in claim 3 is the invention described in claim 1 or 2, wherein the inverse analysis step is performed based on a strain in a depth direction and a strain measurement result in a direction orthogonal to the depth direction. It is characterized by that.
本発明の地山安定性評価方法によれば、切土または掘削施工時及び施工後の地山の安定性を高い精度で評価することができる。 According to the natural ground stability evaluation method of the present invention, the stability of natural ground during cutting or excavation construction and after construction can be evaluated with high accuracy.
以下、本発明を実施するための最良の形態を図1〜図3に基いて詳細に説明する。
本発明の実施の形態に係る地山安定性評価方法は、図1に示す切土または掘削施工(以下、掘削施工として説明する)時及び施工後の地山1のリバウンド挙動、すべり挙動及び沈下挙動等を把握し、施工時及び施工後の地山1の安定性を正確に評価するものである。
本発明の実施の形態に係る地山安定性評価方法を、図3のフローに基いて図1及び図2も参照しながら説明する。
まず、地質調査ステップS1では、地山1の表面から調査ボーリング孔を開け、ボーリングコアにより地質調査が行われる。その後、地質分布図作成ステップS2にて、地質分布図が作成される。
次に、事前予測ステップS3では、堀削施工の前段階で、堀削施工時の地山挙動を弾塑性FEMにて簡易的に解析する。該弾塑性FEMでは、地質分布図より把握される解析パラメータに基いて解析が行われ、掘削施工による要留意項目等が抽出される。
次に、センサー設置ステップS4では、図1に示すように、地山1の要留意地点にボーリング孔2を所定深さで開け、該ボーリング孔2内に、深度に対するひずみを計測可能なひずみ計測センサー3が設置される。なお、ひずみ計測センサー3は、光ファイバセンサーを採用してもよい。
該ひずみ計測センサー3は、深度に対する、深度方向のひずみと深度方向と直交する方向のひずみとがそれぞれ計測可能であり、図2(a)は、深度に対する深度方向のひずみの計測結果で、図2(b)は、深度に対する、深度方向と直交する方向のひずみの計測結果である。
Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS.
The natural ground stability evaluation method according to the embodiment of the present invention includes the rebound behavior, the sliding behavior and the settlement of the natural ground 1 during and after cutting or excavation construction (hereinafter described as excavation construction) shown in FIG. The behavior and the like are grasped, and the stability of the natural ground 1 during construction and after construction is accurately evaluated.
A natural ground stability evaluation method according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2 based on the flow of FIG.
First, in the geological survey step S1, a survey boring hole is opened from the surface of the natural ground 1, and the geological survey is performed by the boring core. Thereafter, a geological distribution map is created in a geological distribution map creating step S2.
Next, in pre-prediction step S3, the natural ground behavior at the time of excavation construction is simply analyzed by an elasto-plastic FEM at the stage before excavation construction. In the elasto-plastic FEM, an analysis is performed based on analysis parameters grasped from a geological distribution map, and items to be noted due to excavation work are extracted.
Next, in the sensor installation step S4, as shown in FIG. 1, a borehole 2 is opened at a predetermined depth at a point requiring attention in the natural ground 1, and a strain measurement capable of measuring strain relative to the depth is provided in the borehole 2. A sensor 3 is installed. The strain measurement sensor 3 may employ an optical fiber sensor.
The strain measurement sensor 3 can measure the strain in the depth direction and the strain in the direction perpendicular to the depth direction with respect to the depth. FIG. 2A shows the measurement result of the strain in the depth direction with respect to the depth. 2 (b) is a measurement result of strain in a direction perpendicular to the depth direction with respect to the depth.
次に、施工ステップS5では、図1に示すように、地山1の一部を掘削施工する。この時、地山1の試料を採取して、物性及び力学試験(例えば、三軸圧縮/引張試験やせん断試験)が並行して行われ、採取した試料の応力−ひずみ特性等を計測する。
次に、計測ステップS6では、ひずみ計測センサー3により地山内部の深度に対するひずみが連続的に計測される。
次に、逆解析ステップS7では、計測ステップS6による計測結果及び採取した試料の特性等現在まで取得したデータに基いて、弾塑性FEM解析に必要な解析パラメータを逆解析する。この解析パラメータは、従来まで取得が困難であった、特に、地山1の各地質の弾塑性解析パラメータ、すなわち地山1の各地質の応力−ひずみ特性等である。
次に、解析ステップS8では、逆解析ステップS7にて逆解析した解析パラメータに基いて、施工後の地山1の安定性を弾塑性FEMにより解析する。この解析結果は、施工後の地山1全体のひずみ−応力分布図等にて出力される。
該弾塑性FEM解析(tij-model)は、地山1の各地質の材料それぞれの特性に応じて、硬化/軟化,圧縮/膨張などの力学挙動を詳細に解析可能であり、これにより、掘削施工によるリバウンド挙動や弱層の剛性低下などのすべり挙動等の再現性が高く、かつ定量的な予測精度の高い解析能力を有している。
Next, in construction step S5, a part of natural ground 1 is excavated as shown in FIG. At this time, a sample of the natural ground 1 is collected, physical properties and mechanical tests (for example, triaxial compression / tensile test and shear test) are performed in parallel, and the stress-strain characteristics and the like of the collected sample are measured.
Next, in measurement step S6, the strain with respect to the depth inside the natural ground is continuously measured by the strain measurement sensor 3.
Next, in the inverse analysis step S7, the analysis parameters necessary for the elasto-plastic FEM analysis are inversely analyzed based on the data obtained up to now, such as the measurement result in the measurement step S6 and the characteristics of the collected sample. This analysis parameter is an elasto-plastic analysis parameter of the local quality of the natural ground 1, that is, a stress-strain characteristic of the local quality of the natural ground 1, and the like.
Next, in the analysis step S8, the stability of the natural ground 1 after the construction is analyzed by an elasto-plastic FEM based on the analysis parameters reversely analyzed in the reverse analysis step S7. This analysis result is output in a strain-stress distribution diagram of the whole natural ground 1 after construction.
The elasto-plastic FEM analysis (tij-model) can analyze in detail the mechanical behavior such as hardening / softening, compression / expansion, etc. according to the characteristics of each quality material in the natural ground 1. It has high reproducibility such as rebound behavior due to construction and slip behavior such as weakening of weak layer, and it has analysis ability with high quantitative prediction accuracy.
次に、妥当性評価ステップS9では、解析ステップS8による解析結果に妥当性があるか否かが判断される。この判断により妥当性があると判断された場合には、解析パラメータの同定ステップS12を経由して、次段階の施工における1次地山安定性評価ステップS13に進む。一方、妥当性評価ステップS9において、解析ステップS8による解析結果に妥当性がないと判断された場合には追加調査・計測の評価ステップS10に進む。
次に、追加調査・計測の評価ステップS10では、新にボーリング孔を施工して該ボーリング孔内にひずみ計測センサー3を設置する必要性があるか否かが判断される。この判断により必要性があると判断された場合には、新にボーリング孔を施工して該ボーリング孔内にひずみ計測センサー3を設置するひずみ計測センサー設置ステップS11を経由して計測ステップS6に進む。一方、追加調査・計測の評価ステップS11において、新たなボーリング孔内にひずみ計測センサー3を設置する必要性がないと判断された場合には、解析ステップS8に戻り、解析パラメータの内容等を再度検討・確認し、再び、弾塑性FEMにて解析する。
Next, in the validity evaluation step S9, it is determined whether or not the analysis result in the analysis step S8 is valid. If it is determined that this is appropriate, the process proceeds to the primary ground stability evaluation step S13 in the next stage of construction through the analysis parameter identification step S12. On the other hand, in the validity evaluation step S9, if it is determined that the analysis result in the analysis step S8 is not valid, the process proceeds to the additional investigation / measurement evaluation step S10.
Next, in the additional investigation / measurement evaluation step S10, it is determined whether or not it is necessary to newly construct a borehole and install the strain measurement sensor 3 in the borehole. If it is determined that this is necessary, the process proceeds to measurement step S6 via a strain measurement sensor installation step S11 in which a new borehole is constructed and the strain measurement sensor 3 is installed in the borehole. . On the other hand, if it is determined in the additional investigation / measurement evaluation step S11 that there is no need to install the strain measurement sensor 3 in the new borehole, the process returns to the analysis step S8, and the contents of the analysis parameters are again set. Review and confirm, and analyze again with elasto-plastic FEM.
一方、妥当性評価ステップS9にて、解析ステップS8による解析結果に妥当性があると判断された場合には、解析パラメータの同定ステップS12を経由して、1次地山安定性評価ステップS13に進む。該1次地山安定性評価ステップS13では、解析ステップS8による解析結果に基いて、1次補強工事S14の必要性が判断される。その結果、1次補強工事S14が必要ないと判断された場合には、施工ステップS5に進み、次段階の堀削施工が行われ、以後フローが実行される。一方、1次補強工事S14が必要であると判断された場合には、1次補強工事S14、例えばロックボルト、押え盛土及び水抜き等が行われる。その後、2次地山安定性評価ステップS15において、事前に実施された、1次補強工事S14に基づくFEM解析の解析結果に基いて、より強度を高くする2次補強工事S16の必要性が判断される。その結果、2次補強工事S16が必要ないと判断された場合には、施工ステップS5に進み、次段階の堀削施工が行われ、以後フローが実行される。一方、2次補強工事S16が必要であると判断された場合には、2次補強工事S16、例えばグランドアンカー、抑止杭及びマイクロバイル等が行われる。その後、3次地山安定性評価ステップS17において、事前に実施された、2次補強工事S16に基づくFEM解析の解析結果に基いて、さらに強度を高くする高次補強工事の必要性が判断される。その結果、高次補強工事が必要ないと判断された場合には、施工ステップS5に進み、次段階の堀削施工が行われ、以後フローが実行される。高次補強工事が必要であると判断された場合には、その旨、高次補強工事が行われる。
なお、図3のフローに沿って地山安定性評価が行われている間、ひずみ計測センサー3はボーリング孔2内に設置された状態が維持される。
On the other hand, if it is determined in the validity evaluation step S9 that the analysis result in the analysis step S8 is valid, the analysis parameter identification step S12 is passed to the primary ground stability evaluation step S13. move on. In the primary ground stability evaluation step S13, the necessity of the primary reinforcement work S14 is determined based on the analysis result in the analysis step S8. As a result, when it is determined that the primary reinforcement work S14 is not necessary, the process proceeds to the construction step S5, where the next excavation work is performed, and then the flow is executed. On the other hand, when it is determined that the primary reinforcement work S14 is necessary, the primary reinforcement work S14, for example, a lock bolt, presser embankment, draining, etc. is performed. Thereafter, in the secondary ground stability evaluation step S15, the necessity of the secondary reinforcement work S16 for increasing the strength is determined based on the analysis result of the FEM analysis based on the primary reinforcement work S14 performed in advance. Is done. As a result, when it is determined that the secondary reinforcement work S16 is not necessary, the process proceeds to the construction step S5, the next stage of excavation work is performed, and the flow is executed thereafter. On the other hand, when it is determined that the secondary reinforcement work S16 is necessary, the secondary reinforcement work S16, for example, a ground anchor, a restraint pile, a microbile, or the like is performed. Thereafter, in the tertiary ground stability evaluation step S17, the necessity of higher-order reinforcement work that further increases the strength is determined based on the analysis result of the FEM analysis based on the secondary reinforcement work S16 performed in advance. The As a result, when it is determined that the higher-order reinforcement work is not necessary, the process proceeds to the construction step S5, the next stage of excavation work is performed, and then the flow is executed. If it is determined that higher-order reinforcement work is necessary, higher-order reinforcement work is carried out to that effect.
In addition, while the natural ground stability evaluation is performed along the flow of FIG. 3, the state in which the strain measurement sensor 3 is installed in the boring hole 2 is maintained.
以上説明したように、本発明の実施の形態に係る地山安定性評価方法では、ひずみ計測センサー3により、切土または掘削施工時の深度に対するひずみを計測することが可能になり、逆解析ステップS7において、弾塑性FEMの解析パラメータとして、特に、地山1の各地質の応力−ひずみ特性を逆解析することができ、解析ステップS8において、該解析パラメータに基いて弾塑性FEMにて地山挙動を解析するので、切土または掘削施工時及び施工後の地山安定性を高い精度で評価することができる。
しかも、本発明の実施の形態に係る地山安定性評価方法では、地山1の切土または掘削施工が完了した後でも、地山安定性が高い精度で把握できているので、耐用年数の長期化及び維持コストの削減を実現することが可能になる。
As described above, in the natural ground stability evaluation method according to the embodiment of the present invention, the strain measurement sensor 3 can measure the strain with respect to the depth at the time of cutting or excavation, and the inverse analysis step. In S7, as an analysis parameter of the elastoplastic FEM, in particular, the stress-strain characteristics of the various geological features of the natural ground 1 can be inversely analyzed. In the analysis step S8, the natural ground is analyzed by the elastoplastic FEM based on the analysis parameter. Since the behavior is analyzed, it is possible to evaluate the stability of natural ground during cutting or excavation construction and after construction with high accuracy.
Moreover, in the natural ground stability evaluation method according to the embodiment of the present invention, the natural ground stability can be grasped with high accuracy even after the cut or excavation of the natural ground 1 is completed. It becomes possible to realize long-term and reduction of maintenance costs.
1 地山,2 ボーリング孔,3 ひずみ計測センサー 1 Ground, 2 Boring hole, 3 Strain measuring sensor
Claims (3)
地山の内部に、深度に対するひずみを計測可能なひずみ計測センサーを設置するセンサー設置ステップと、
該センサー設置ステップ後、地山を切土または掘削施工する施工ステップと、
該施工ステップ後、前記ひずみ計測センサーにより地山の深度に対するひずみを計測するひずみ計測ステップと、
該ひずみ計測ステップによる計測結果に基いて、弾塑性FEM解析に必要な解析パラメータを逆解析する逆解析ステップと、
該逆解析ステップにて逆解析した解析パラメータに基いて、切土または掘削施工による地山の安定性を弾塑性FEMにより解析する解析ステップと、
を備えたことを特徴とする地山安定性評価方法。 Natural ground stability that evaluates the stability of natural ground by using existing measurement methods that can measure strain in the depth direction during cutting or excavation construction and after construction, and strain perpendicular to the depth direction. A sex assessment method,
A sensor installation step in which a strain measurement sensor capable of measuring strain with respect to depth is installed inside the ground,
After the sensor installation step, a construction step for cutting or excavating the natural ground,
After the construction step, a strain measurement step of measuring strain with respect to the depth of the natural ground by the strain measurement sensor,
An inverse analysis step for inversely analyzing analysis parameters necessary for the elasto-plastic FEM analysis based on the measurement result of the strain measurement step;
An analysis step for analyzing the stability of the natural ground by cutting or excavation by an elasto-plastic FEM based on the analysis parameters reversely analyzed in the reverse analysis step;
A natural mountain stability evaluation method characterized by comprising:
該妥当性評価ステップにて、解析結果に妥当性があると判断された場合には該解析結果に基いて地山の安定性を評価する安定性評価ステップと、
を備えたことを特徴とする請求項1に記載の地山安定性評価方法。 A validity evaluation step for evaluating the validity of the analysis result by the analysis step;
In the validity evaluation step, when it is determined that the analysis result is valid, a stability evaluation step for evaluating the stability of the natural ground based on the analysis result;
The natural ground stability evaluation method according to claim 1, comprising:
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